The church is very small and peaceful. We went early on a Sunday morning, when the Via Appia is mostly closed to auotmobiles, to walk the Appian Way. The relic of the footprints of Christ is now stored at St. Sebastian, further up the Appian Way. But the Church of Domine Quo Vadis has a replica, and tradition has it that the Church was built near the spot where Christ appeared to Peter.
It is very easy to miss the church unless You go deliberately looking for it. It is located way outside the city along the Via Appia Antica. I visited the place more than twenty years ago, and as far as I remember, the old Appian way at that time and at that spot was little more than a path paved with large ancient cobblestones without any public transportation. Basically the only way to get there was to use Your own feet, which proved very satisfying since the road and surroundings are charming. I would not be surprised, if the opening scene of the film, where Vinicius' legions march towards Rome, had been filmed in the original place.